This invention relates in general to a disc brake assembly and in particular to an improved disc brake piston structure.
Disc type brakes assemblies for vehicles are well known and generally include one or more pistons which are actuated, typically by pressurized hydraulic fluid, to force a pair of brake shoes against an associated brake rotor. Many various piston structures, constructed of either metal or plastic, have been proposed and used in disc brake assemblies. The pistons are generally cylindrical and are provided with an abutment surface at one end thereof for engagement with one of the brake shoes. The one end of the piston also includes an outer annular boot groove which, in many instances, is machined into the cylindrical wall of the piston, and is adapted to receive one end of a flexible dust boot. Because the machining operation of the boot groove weakens the side wall of the piston at the location of the groove, it is important that the original thickness of the piston side wall in this region be sufficient to accommodate the groove.